<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./src/react.js"></script>
    <script src="./src/react-dom.js"></script>
    <script src="./src/babel.js"></script>
</head>

<body>
    <div id="app"></div>
</body>
<script type="text/babel">
let num=1
function btn(){
    
    num+=1
    console.log(num);

}
    ReactDOM.render(
    <div>
        <h1>{num}</h1>
        <button onClick={btn}>按钮</button>
        </div>,
    document.getElementById('app')
)
</script>

</html>